blk_mq_hw_queue_to_node(9)

okay so bestie, you’re looking at blk_mq_hw_queue_to_node(9) from the Kernel API Manual, and it’s giving very specific kernel-internals energy 💅✨

✨ NAME ✨

Look up the memory node for a hardware queue index. That’s literally the whole vibe 🧚

🌸 SYNOPSIS 🌸

int blk_mq_hw_queue_to_node (struct blk_mq_queue_map *qmap , unsigned int index );

🎀 ARGUMENTS 🎀

• qmap — the CPU-to-hardware-queue map 🗺️ like, the map that connects CPUs to hardware queues.
• index — the hardware queue index 🔢 the specific queue number you’re checking.

💖 DESCRIPTION 💖

okay so real talk: we have no quick way of doing reverse lookups 😭 that’s just the situation.

But lowkey it’s fine, because this is only used at queue init time, so runtime isn’t important. It’s not out here trying to be fast during the main event — it’s doing its little setup-era thing and that’s valid 🫶

🦋 SEE ALSO 🦋

Kernel file ./block/blk-mq-cpumap.c and these besties:

• blk_mq_num_possible_queues(9)
• blk_mq_num_online_queues(9)
• blk_mq_map_hw_queues(9)

mwah 💋 this page lives under ./block, dated October 2026, and it’s the blk_mq_hw_queue_to_node(9) man page — periodt 🌈👑